An Etymological Dictionary of Astronomy and Astrophysics

Math.: Of or pertaining to the geometry of → affine transformations. See also: → affine combination, → affine geometry, → affine set, → affinity.

Etymology (EN): From Fr., from L. affinis “bordering on; neighboring; related.”

Etymology (PE): Karvan, literally “bordering on; possessing border (with); related,” from (Bašgard) ker “border, boundary,” (Fin Bandar Abbas) karaq “border, edge;” classical Pers. karân, kenâr “boundary, side, edge;”

• -van suffix of possession, relation.

A linear combination of vectors in which all the vector coefficients add up to one.

See also: → affine; → combination.

The study of the properties which are → invariant under → affine transformations.

See also: → affine; → geometry.

A set → if and only if (iff) for any two points in the → set, the line through them is contained in the set. In other words, for any two points in the set, their → affine combinations are in the set itself.

See also: → affine; → set.

Any → transformation preserving → collinearity.

See also: → affine; → transformation.

1. General: A relationship or resemblance.
   

   2. Math.: The state, quality, or fact of being → affine.

See also: → affine; → -ity.

To state or assert positively; maintain as true.

Etymology (EN): M.E. affermen, affirmen “to decide upon; to state positively,” from O.Fr. afermer “affirm, confirm; strengthen,” from L. affirmare “to make steady, strengthen,” from → ad- “to” + firmare “strengthen, make firm,” from firmus, → firm.

Etymology (PE): Baedešidan, from bar- “upon, to,” + deš, → firm, + infinitive suffix -idan.

The act of affirming or something affirmed.

See also: Verbal noun of → affirm.

A linguistic element added to a word or root to produce a derived or inflected form. General term for → infix, → prefix, → suffix, and → circumfix.

Etymology (EN): From L. affixus “fastened to,” p.p. of affigere
“fasten to, attach,” from af-, variant of → ad- “to”

• figere “fasten.”

Etymology (PE): Vand, variant band “tie, band,” present stem of Mod.-Mid./Pers. bastan/vastan “to bind, shut;” Av./O.Pers. band- “to bind, fetter,” banda- “band, tie;” cf. Skt. bandh- “to bind, tie, fasten;” PIE *bhendh- “to bind,” cf. Ger. binden, E. bind.

Describing a lens or optical system with a convergent power of zero, whose object and image points stretch to infinity. Thus,
→ afocal system.

Etymology (EN): Afocal, from → a- + → focal.

Etymology (PE): Akânun, from a- negation prefix, → a- + kânun, → focus. Bikânun, from bi- negation prefix + kânun, → focus.

An optical system with object and image points at infinity.

See also: → afocal; → system.

1. Behind in place or position; following behind.
   

2. Later in time than; in succession to; at the close of (Dictionary.com).

Etymology (EN): M.E., from O.E. æfter “after, next, following in time,” from O.E. of “off,” cf. apo-

• -ter a comparative suffix.

Etymology (PE): Pas “after,” → back-; pasân with place/time suffix -ân.

1. A broad glowing arc of radiance, sometimes seen high in the western sky at → twilight, caused by the → scattering effect of → fine dust particles suspended in the → upper atmosphere.
   

2. Lingering → radiation that remains after a violent → event such as a → gamma-ray burst. The afterglow of any gamma-ray burst is caused by an event different from the original explosion, likely by → shock waves colliding with the ambient medium. Afterglows occur in a large range of → electromagnetic  → wavelengths.

See also: → after; → glow.

The part of day from → noon to → evening.

See also: → after; → noon.

At a later or subsequent time; subsequently.

See also: → after; → -ward.